The guitar has a long rich history, with several types emerging over the milennia. Not withstanding the wide variety of styles, generally there are two main types of guitars—acoustic and electric, with some hybrids commercially available in recent years. Acoustic guitars have hollow bodies and have been in use for over a thousand years. Acoustic guitars are typically strung with nylon or steel strings, which are plucked with the users fingers or strummed with the user's hand. The guitar generally comprises a body and a neck, with a set of strings supported tautly by one end of the neck and the other end (or middle) of the body, typically over a bridge for transferring string vibrations. Guitars vary widely not only to accommodate the various types of sound qualities desired, but also to display aethestic qualities that reflect the user's particular style or personality. With acoustic guitars, the body comprises a hollow sound box, as explained below. Electric guitars usually do not have a hollow sound box, although some do.
Guitars produce sound through amplifying the vibration of the strings as the user strums the strings. Sound is produced when the air surrounding a source of sound is displaced, creating waves. Those waves register in many ways, not the least of which is a user's ear. However, the size of the strings themselves are relatively small, so the amount of air this displaced when a string is stummed is slight. In order to enhance the sound, the strings are supported by a bridge that is connected to a sound board, both of which transmit vibrations from the string to the surrounding area. The much large area of air displacement allows more sound to eminate from the guitar. Further enhancement is provided in one of at least two ways: with resonating guitars, for example common acoustic guitars, enhancement of sound occurs by providing a volume of air housed within the hollow body of the guitar, or the sound box, so that vibrations of the air within the sound box vibrate against both the upper sound board and the lower sound board, although the lower sound board does not have as much resonating effect as the upper sound board because it is usually held against the user.
The air in the cavity defined by the body—sound box—resonates with the vibrational modes of the string. The volume of sound may be increased or decreased depending upon whether the vibrations of the air within the sound box is in phase or out of phase with the vibration of the strings. Importantly, the air in the sound box is coupled to the resonance of the top plate. The sound made by a guitar is a complex mixture of harmonics that gives the guitar its distinctive sound. By using a large surface area to displace a larger volume of air, the guitar takes fairly slight string sounds and produces rich and deep sounds.
One type of acoustic guitar is known as the Dobro® style guitar. According to an on-line site, the name Dobro apparently originated in the late 1920's when the Dopyera brothers formed a company called Dobro, which was both a contraction of “Dopyera brothers” and a Slovak word meaning “goodness.” The Dobro® guitar was a resonator guitar created by one of the Dopyera brothers with a single resonator plate having a shallow conical shape pointing outwardly (away from the sound box) and supported by the upper sound board of a sound box. Earlier resonator guitar designs included a single conical resonator plate facing inwardly (toward the interior of the sound box), and a tricone design with three concave resonator plates supported by the upper sound board.
With electric guitars, enhancement of the string sound occurs synthetically through the use of electronic pickup and amplification. It should be noted that there are some electric guitars that include a sound box in a hybrid fashion, enhancing the sound with the resonant configuration of a sound box coupled with electric pickup and amplification. One hybrid model borrow from the Dobro® style guitar in which a conical resonator plate is supported by an upper sound board that also supports an electronic pick up and electronic amplification controls.
As a person of ordinary skill in the art may appreciate, depending upon the configuration of the guitar body, the materials used, and adjunct components added, the quality and appeal of the sound generated may vary widely. Each may provide a range of sound suitable for the style of music desired, and of course may depend upon the personality of the listener. However, there remains a dedicated effort in the industry to generate more robust and valuable sounds from acoustic, electric and hybrid guitars. Many existing guitars provide excellent sound, but others could be improved. One area ripe for improvement is the resonator guitar, which the present invention address, as described and claimed below.